"The alternative energy sector is hot," said George Relan, director of corporate relations for MTI MicroFuel Cells Inc. "Everybody in the world wants clean energy. This is what you'll be seeing next year--more investment and more products. It's an industry that is starting to get some attention."

MTI Micro, a subsidiary of Mechanical Technology Inc., makes small fuel-cell power packs that run devices such as PDAs.

It is targeting military applications and met one of its milestones in 2005 by making its power pack match a popular military battery in size, but with double its energy output.

The company expects to enter the military and government commercial market in 2006.

Fuel-cell system manufacturer Plug Power Inc. (Nasdaq: PLUG) of Latham sold 192 units of it GenCore backup power system in 2005 by targeting the telecommunications industry.

It made deals with three new distribution partners and lobbied hard with other companies to win a federal tax credit for purchasers of fuel-cell systems. Those developments have bolstered hopes for 2006.

"I think we made significant progress this year," said Cynthia White, Plug Power's spokeswoman. "We've been able to secure our first major GenCore order with a large U.S. telecom. It shows the beginning of market acceptance."

DayStar Technologies Inc. (Nasdaq: DSTI) of Halfmoon, a manufacturer of solar cells, landed its first major client, Blitzstrom GmbH of Germany.

The contract may be worth as much as $75 million over its lifetime. The company expects to close the year with 40 employees--up from two employees last year--and move into new manufacturing space.

AWS Truewind LLC of Albany, which helps wind energy companies locate wind turbines, expects revenue to climb from $4 million to $5 million next year.

Advanced Energy Conversion LLC, a Malta company that is developing a starter/alternator system for vehicles it believes will get more attention as a result of higher gas prices.

Called Stop & Save, it cuts the engine off when vehicles are idle and instantly start it up again when the accelerator is pushed.